The invention relates to brake systems. More particularly, the invention relates to brake control devices, which are used with a brake for engaging a wheel of a vehicle.
Many vehicles, such as bicycles, utilize a braking system that causes the application of pressure to a rotating wheel or a disc rotor mounted to a rotating wheel. Many of these braking systems utilize a mechanism with a hand lever to generate pressure with a hydraulic fluid. This pressure is transferred through a hydraulic line or conduit to a brake apparatus, which may include a caliper having brake pads, such that the hydraulic pressure is applied to the pads to squeeze the pads against the rotating part to impart a braking force thereto. The rotating part could be a wheel rim or a rotor, for example.
Two general types of brake systems are commonly seen in the bicycle market and these use different mechanisms to convey braking force from a hand lever mounted to the outside of a handlebar down to the wheel to stop the bicycle. The first, and typically least expensive way, is the use of a steel cable positioned in a housing which is pulled by the hand lever. This cable is connected to a brake caliper near the rim of a wheel and when pulled, generates force between paired brake pads. The resulting friction slows the bicycle. The other way is the use of hydraulic fluid in a hydraulic line to convey the hand-generated force down to the brake caliper. This hydraulic fluid is pushed by a master piston by operating a hand lever and pushes against a slave piston at or near the caliper, which causes the brake pads to move against the rim and slow the bicycle. Cable actuated brake systems may use different lever distances to increase the hand force and generate a higher brake force between the brake pads and rim, in contrast to hydraulic brakes which use different piston diameters to increase the hand force.
An advantage of hydraulic actuated brakes is the lower energy loss in the hydraulic line in contrast to the steel cable, especially when the steel cable is fished through the interior of the bicycle handlebar and frame member(s), because of the amount of friction created between the cable and the housing. This makes hydraulic brake systems an attractive option for road and triathlon bicycles. Triathlon and time trial style bicycles are designed to be very aerodynamic and the brake lines are typically hidden inside the handlebar and the frame to reduce drag. The triathlon and time trial style handlebar has a special shape to allow the rider to ride the bike in an aerodynamic position. For this reason, effective hydraulic brake systems are particularly advantageous when applied to triathlon and time trial bicycles.